Third-party cookies have long been a cornerstone of digital advertising, enabling advertisers to track user behavior across the web. Cookies are small blocks of data stored on a user’s device that collect information about them. First-party cookies are stored by the domain a user is directly visiting and are used to enhance the user’s experience on that website. In contrast, third-party cookies are placed on a user’s device by a website other than the one they are visiting. As such, third-party cookies have been instrumental in the development of personalized advertising, allowing advertisers to track users across different websites and apps and build comprehensive profiles based on their browsing behavior. This data is used to create targeted ads, measure campaign effectiveness, and retarget users who have previously shown interest in a product or service. For nearly three decades, third-party cookies have supported the ad ecosystems that funds much of the free content available online.
However, the capabilities that make third-party cookies so compelling for advertisers have also made them a focal point of privacy concerns. Regulations including the European Union’s (EU) General Data Protection Regulation (GDPR) and the California Consumer Privacy Act (CCPA) have provided consumers with greater transparency and choice regarding third-party cookies. These laws have helped to spur significant changes, such as all websites being required to give users the option to opt in or out of certain types of cookies. Other popular web browsers, including Apple’s Safari and Mozilla’s Firefox, already block third-party cookies by default. Apple, additionally, as of 2022, began requiring third-party apps to obtain user consent for tracking.
